before my office i use to work at home and for me 1 break worked during working hours, in 8 hours i use to sit and grind 4 hours straight and then a break of an hour or half then straight 4 hours this was my routing and i ate only in that break.
Very good point to note is getting distracted on different website, still whenever i get done with a task from pile of tasks i get distracted on social media. well you only have to train your brain not to end on such site